The announcement this month of a new cease-fire agreement in Syria is good news. But a lack of trust among the Syrian belligerents and their foreign supporters means this agreement, like the one that came before it, is vulnerable to collapse.

It is already showing severe signs of strain. Over the weekend, the United States accidentally bombed Syrian government troops. On Monday, the Syrian military declared it would no longer respect the deal, resumed airstrikes on Aleppo, and even a humanitarian aid convoy was bombed.

Still, there is reason for hope. If Russia and the United States were willing to come far enough in their negotiations to reach this deal, these setbacks can be overcome. The targeting of the humanitarian convoy, a war crime, should serve as an added impetus for the United States and Russia to recommit to the cease-fire. The two parties were well aware of the difficulties as they spent a month negotiating the cease-fire’s terms.

The agreement can be salvaged if all sides unite, for now, around a simple and undeniably important goal: Stop the killing. It may be more likely than it sounds.

Reliable sources estimate the number of Syrians killed to date at almost half a million, with some two million more people wounded. Well over half of the country’s 22 million prewar population has been displaced. These shocking numbers alone should convince all concerned that war itself is the greatest violation of human rights and the ultimate enemy of Syria.

If this cease-fire is to last, the United States and Russia must find ways to work beyond the lack of trust that undermined the previous cease-fire, in February. The countrywide cessation of hostilities that began then started to crumble within two months, with battles in much of the countryside around Damascus, central and northern Syria, and Aleppo. The resumption of the conflict led in April to the suspension of United Nations-sponsored peace talks in Geneva.

However, a strong effort was made earlier in the year when the United States and Russia pressed their respective allies to pause the fighting and give the negotiations a chance. But the American and Russian expectation that they reach an agreement on issues of transitional governance by Aug. 1 was unrealistic. After five years of killing, and before any semblance of trust could be established, pushing the Syrian parties and their supporters to agree on power-sharing was seen as too threatening by some and too inadequate by others. Unsurprisingly, they reverted to violence.

When talks resume in Geneva later this month, the primary focus should be stopping the killing. Discussions about the core questions of governance — when President Bashar al-Assad should step down, or what mechanisms might be used to replace him, for example — should be deferred.

The new effort could temporarily freeze the existing territorial control — without the government, the opposition or the Kurds giving up their arms. Additionally, measures could be agreed upon to stabilize conditions in territories controlled by these belligerents, with guarantees of unrestricted access to humanitarian aid, a particularly important demand given the strike on an aid convoy near Aleppo.

This approach is not without significant challenges. Foreign players, less concerned about the destruction of Syria than about their own interests, will not necessarily be happy to see the front lines stay where they are. Russia is interested in a Mediterranean port; Iran wants a linkage with Hezbollah in Lebanon; Turkey’s primary goal is undermining Kurdish ambitions; and Saudi Arabia cares most about preventing another Iranian foothold in the Arab world. These interests are already threatening the tenuous cease-fire.

Still, stopping the killing and freezing the status quo changes the game from win-lose to no-lose. The belligerents would not have to concede their vital interests, nor would they be rushed into collaboration and compromise at a time when their confidence in one another and in the international community is low.

Under current conditions, the Syrian government and the rebels both would perceive any concession or compromise as a sellout. However, not losing and stopping the killing may be an attractive proposition. At the least, it would certainly be harder to reject.

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Clearly, these measures could not apply to parts of Syria held by the Islamic State and other United Nations-designated terrorist organizations. But if the killing is stopped in parts of the country not under the control of these groups, fighters in their ranks are likely to be tempted to abandon them and move to areas that offer better living conditions. This could mark a significant turning point in the effort to defeat the terrorists.

American-Russian leadership is critical for this approach to work. Each side must persuade its regional allies to cooperate. But that alone won’t be enough. The Syrians who have been the cannon fodder in this war must make their voices heard, with a loud and clear statement: “Stop the killing.” In the past five years, Syrians have mobilized around civil society organizations working on humanitarian, human rights and peace-building initiatives. They, too, must stand up and shout: “Stop the killing!” International institutions must support this rallying cry, too.

A groundswell of public calls to stop the killing may compel the Syrian belligerents, and regional and international stakeholders, to take notice — and to take action. When the killing stops, Syrians can work on recovering their lost dignity, which will be essential for addressing the issues that set off the war in the first place.

Jimmy Carter, the founder of the Carter Center, was the 39th president of the United States.